New York law officers, and may law enforcement departments across the country, use roadside breath test devices to determine drivers’ blood alcohol content level. If you have ever been pulled over on suspicion of drunk driving, an officer may have asked you to submit to a breath test. 

Yet, studies show that breath tests may not always yield accurate results. In fact, one in four, or 23%, of people who take a breath test have inflated BAC results, according to the State University of New York at Potsdam. 

Blood tests vs. breath tests 

Breath test devices work by measuring the amount of ethanol alcohol contained in an exhaled breath sample. It then converts this number to a blood alcohol content level. Yet, when researchers compared blood alcohol level readings from a breath test device to those obtained from an actual blood test, they found a 15% discrepancy in some cases. 

Factors that influence readings 

There are physiological and environment factors that may influence BAC readings from breath test devices. These include the following: 

  • Static interference from police radios and/or cell phones 
  • Residual food, vomit, blood and drink in the mouth 
  • Dirt, pollution and smoke in the air 
  • Relative humidity of the atmosphere 
  • Fumes from cigarette smoke, cleaners and gasoline 

It is critical that officers calibrate breath test devices regularly. Furthermore, law enforcement departments should train all officers on how to use the devices properly in order to maximize the accuracy of results. 

If a law enforcement officer asks you to take a breath test device, it is best to be aware of how the devices work and the factors that contribute to breath test readings.